Peltier Cooler Equipped With Synthetic Jet Ejectors

ABSTRACT

A device ( 301 ) is provided which includes a Peltier device ( 303 ); a heat sink ( 305 ) in thermal contact with the Peltier device; and a synthetic jet ejector ( 307, 309 ) which directs a synthetic jet ( 319, 321 ) onto or adjacent to a surface of the heat sink.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 61/611,863, filed Mar. 16, 2012, having the same title and the same inventors, and which is incorporated herein in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to synthetic jet ejectors, and more particularly to systems and methods for thermal management which utilize synthetic jet ejectors in conjunction with Peltier coolers.

BACKGROUND OF THE DISCLOSURE

A variety of thermal management devices are known to the art, including conventional fan based systems, piezoelectric systems, and synthetic jet ejectors. The latter type of system has emerged as a highly efficient and versatile thermal management solution, especially in applications where thermal management is required at the local level.

Various examples of synthetic jet ejectors are known to the art. Earlier examples are described in U.S. Pat. No. 5,758,823 (Glezer et al.), entitled “Synthetic Jet Actuator and Applications Thereof”; U.S. Pat. No. 5,894,990 (Glezer et al.), entitled “Synthetic Jet Actuator and Applications Thereof”; U.S. Pat. No. 5,988,522 (Glezer et al.), entitled Synthetic Jet Actuators for Modifying the Direction of Fluid Flows”; U.S. Pat. No. 6,056,204 (Glezer et al.), entitled “Synthetic Jet Actuators for Mixing Applications”; U.S. Pat. No. 6,123,145 (Glezer et al.), entitled Synthetic Jet Actuators for Cooling Heated Bodies and Environments”; and U.S. Pat. No. 6,588,497 (Glezer et al.), entitled “System and Method for Thermal Management by Synthetic Jet Ejector Channel Cooling Techniques”.

Further advances have been made in the art of synthetic jet ejectors, both with respect to synthetic jet ejector technology in general and with respect to the applications of this technology. Some examples of these advances are described in U.S. 20100263838 (Mahalingam et al.), entitled “Synthetic Jet Ejector for Augmentation of Pumped Liquid Loop Cooling and Enhancement of Pool and Flow Boiling”; U.S. 20100039012 (Grimm), entitled “Advanced Synjet Cooler Design For LED Light Modules”; U.S. 20100033071 (Heffington et al.), entitled “Thermal management of LED Illumination Devices”; U.S. 20090141065 (Darbin et al.), entitled “Method and Apparatus for Controlling Diaphragm Displacement in Synthetic Jet Actuators”; U.S. 20090109625 (Booth et al.), entitled Light Fixture with Multiple LEDs and Synthetic Jet Thermal Management System“; U.S. 20090084866 (Grimm et al.), entitled Vibration Balanced Synthetic Jet Ejector”; U.S. 20080295997 (Heffington et al.), entitled Synthetic Jet Ejector with Viewing Window and Temporal Aliasing”; U.S. 20080219007 (Heffington et al.), entitled “Thermal Management System for LED Array”; U.S. 20080151541 (Heffington et al.), entitled “Thermal Management System for LED Array”; U.S. 20080043061 (Glezer et al.), entitled “Methods for Reducing the Non-Linear Behavior of Actuators Used for Synthetic Jets”; U.S. 20080009187 (Grimm et al.), entitled “Moldable Housing design for Synthetic Jet Ejector”; U.S. 20080006393 (Grimm), entitled Vibration Isolation System for Synthetic Jet Devices”; U.S. 20070272393 (Reichenbach), entitled “Electronics Package for Synthetic Jet Ejectors”; U.S. 20070141453 (Mahalingam et al.), entitled “Thermal Management of Batteries using Synthetic Jets”; U.S. 20070096118 (Mahalingam et al.), entitled “Synthetic Jet Cooling System for LED Module”; U.S. 20070081027 (Beltran et al.), entitled “Acoustic Resonator for Synthetic Jet Generation for Thermal Management”; U.S. 20070023169 (Mahalingam et al.), entitled “Synthetic Jet Ejector for Augmentation of Pumped Liquid Loop Cooling and Enhancement of Pool and Flow Boiling”; U.S. 20070119573 (Mahalingam et al.), entitled “Synthetic Jet Ejector for the Thermal Management of PCI Cards”; U.S. 20070119575 (Glezer et al.), entitled “Synthetic Jet Heat Pipe Thermal Management System”; U.S. 20070127210 (Mahalingam et al.), entitled “Thermal Management System for Distributed Heat Sources”; U.S. 20070141453 (Mahalingam et al.), entitled “Thermal Management of Batteries using Synthetic Jets”; U.S. Pat. No. 7,252,140 (Glezer et al.), entitled “Apparatus and Method for Enhanced Heat Transfer”; U.S. Pat. No. 7,606,029 (Mahalingam et al.), entitled “Thermal Management System for Distributed Heat Sources”; U.S. Pat. No. 7,607,470 (Glezer et al.), entitled “Synthetic Jet Heat Pipe Thermal Management System”; U.S. Pat. No. 7,760,499 (Darbin et al.), entitled “Thermal Management System for Card Cages”; U.S. Pat. No. 7,768,779 (Heffington et al.), entitled “Synthetic Jet Ejector with Viewing Window and Temporal Aliasing”; U.S. Pat. No. 7,784,972 (Heffington et al.), entitled “Thermal Management System for LED Array”; and U.S. Pat. No. 7,819,556 (Heffington et al.), entitled “Thermal Management System for LED Array”.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are illustrations depicting the manner in which a synthetic jet actuator operates.

FIG. 2 is a schematic diagram of a Peltier element.

FIG. 3 is an illustration of a top view of a first embodiment of a device which utilizes synthetic jets to cool a Peltier cooler.

FIG. 4 is a side view of FIG. 3.

FIG. 5 is an illustration of a top view of a second embodiment of a device which utilizes synthetic jets to cool a Peltier cooler.

FIG. 6 is a side view of FIG. 5.

FIG. 7 is an illustration of a top view of a third embodiment of a device which utilizes synthetic jets to cool a Peltier cooler.

FIG. 8 is a side view of FIG. 7.

FIG. 9 is an illustration of a thermoelectric module which utilizes synthetic jets to cool a heat source.

FIG. 10 is an illustration of a thermoelectric module which utilizes synthetic jet ejectors powered by waste heat to cool a heat source.

SUMMARY OF THE DISCLOSURE

In one aspect, a thermal management system is provided which comprises (a) a Peltier device; (b) a heat sink in thermal contact with said Peltier device; and (c) a synthetic jet ejector which directs a synthetic jet onto or adjacent to a surface of said heat sink.

In another aspect, a thermal management system is provided which comprises (a) a Peltier device having first and second surfaces; (b) a heat source disposed on said first surface; and (c) a synthetic jet ejector which directs a synthetic jet onto or adjacent to said second surface.

In a further aspect, a method for thermally managing a heat source is provided which comprises (a) providing a thermal management system comprising a Peltier device, a heat sink which is disposed on a first surface of said Peltier device, a heat source which is disposed on a second surface of said Peltier device, and a synthetic jet ejector which directs a synthetic jet onto or adjacent to a surface of said heat sink; and (b) operating the Peltier device such that a temperature gradient is established between said first and second surfaces.

DETAILED DESCRIPTION

The systems, devices and methodologies disclosed herein utilize synthetic jet actuators or synthetic jet ejectors. Prior to describing these systems, devices and methodologies, a brief explanation of a typical synthetic jet ejector, and the manner in which it operates to create a synthetic jet, may be useful.

FIG. 1 illustrates the operation of a typical synthetic jet ejector in forming a synthetic jet. As seen therein, the synthetic jet ejector 101 comprises a housing 103 which defines and encloses an internal chamber 105. The housing 103 and chamber 105 may take virtually any geometric configuration, but for purposes of discussion and understanding, the housing 103 is shown in cross-section in FIG. 1 to have a rigid side wall 107, a rigid front wall 109, and a rear diaphragm 111 that is flexible to an extent to permit movement of the diaphragm 111 inwardly and outwardly relative to the chamber 105. The front wall 109 has an orifice 113 therein which may be of various geometric shapes. The orifice 113 diametrically opposes the rear diaphragm 111 and fluidically connects the internal chamber 105 to an external environment having ambient fluid 115.

The movement of the flexible diaphragm 111 may be achieved with a voice coil or other suitable actuator, and may be controlled by a suitable control system 117. The diaphragm 111 may also be equipped with a metal layer, and a metal electrode may be disposed adjacent to, but spaced apart from, the metal layer so that the diaphragm 111 can be moved via an electrical bias imposed between the electrode and the metal layer. Moreover, the generation of the electrical bias can be controlled by any suitable device including, but not limited to, a computer, logic processor, or signal generator. The control system 117 can cause the diaphragm 111 to move periodically or to modulate in time-harmonic motion, thus forcing fluid in and out of the orifice 113.

Alternatively, a piezoelectric actuator could be attached to the diaphragm 111. The control system would, in that case, cause the piezoelectric actuator to vibrate and thereby move the diaphragm 111 in time-harmonic motion. The method of causing the diaphragm 111 to modulate is not particularly limited to any particular means or structure.

The operation of the synthetic jet ejector 101 will now be described with reference to FIGS. 1 b-1 c. FIG. 1 b depicts the synthetic jet ejector 101 as the diaphragm 111 is controlled to move inward into the chamber 105, as depicted by arrow 125. The inward motion of the diaphragm 111 reduces the volume of the chamber 105, thus causing fluid to be ejected through the orifice 113. As the fluid exits the chamber 105 through the orifice 113, the flow separates at the (preferably sharp) edges of the orifice 113 and creates vortex sheets 121. These vortex sheets 121 roll into vortices 123 and begin to move away from the edges of the orifice 109 in the direction indicated by arrow 119.

FIG. 1 c depicts the synthetic jet ejector 101 as the diaphragm 111 is controlled to move outward with respect to the chamber 105, as depicted by arrow 127. The outward motion of the diaphragm 111 causes the volume of chamber 105 to increase, thus drawing ambient fluid 115 into the chamber 105 as depicted by the set of arrows 129. The diaphragm 111 is controlled by the control system 117 so that, when the diaphragm 111 moves away from the chamber 105, the vortices 123 are already removed from the edges of the orifice 113 and thus are not affected by the ambient fluid 115 being drawn into the chamber 105. Meanwhile, a jet of ambient fluid 115 is synthesized by the vortices 123, thus creating strong entrainment of ambient fluid drawn from large distances away from the orifice 109.

Cooling systems are also known which rely on thermoelectric cooling as implemented by a thermoelectric module. Such systems—which are variously referred to as Peltier coolers, Peltier heaters, Peltier devices, Peltier heat pumps, solid state refrigerators, thermoelectric coolers (TECs), or thermoelectric heat pumps—use the Peltier effect to create a heat flux between the junction formed between two different types of materials. These systems are typically implemented as solid-state active heat pumps which transfer heat from one side of the device to the other side against a temperature gradient (from cold to hot) when direct current runs through the system, and which consequently consume electrical energy as they do so. Although Peltier devices may also be used for heating, most applications of these devices to date have focused on cooling (refrigeration).

FIG. 2 is a schematic diagram of a typical Peltier cooling device 201. The device 201 comprises an electrically active layer 203 comprising a plurality of adjacent P-regions 205 and N-regions 207 which are sandwiched between first and second conductive layers 209. The electrically conductive layers 209 are in electrical contact with first 211 and second 213 terminals and are capped, respectively, with first 215 and second 217 thermally conductive layers. The first 215 and second 217 thermally conductive layers form the cold and hot sides of the device, respectively.

The thermoelectric legs in the Peltier cooling device 201 are thermally in parallel and electrically in series. In a Peltier cooling device, electric power is used to generate a temperature difference between the two sides (that is, the first 215 and second 217 thermally conductive layers) of the device. The thermoelectric performance of the device is typically a function of ambient temperature, hot and cold side heat exchanger (heat sink) performance, thermal load, Peltier module (thermopile) geometry, and Peltier electrical parameters.

It has now been found that synthetic jet ejectors may be used in conjunction with Peltier devices to yield a variety of useful thermal management systems. In a preferred embodiment, such systems utilize a heat sink to spread heat from the hot side of a Peltier device, where it may be dissipated through the use of synthetic jets.

FIGS. 3-4 illustrate a first particular, non-limiting embodiment of a thermal management system which utilizes a Peltier device in conjunction with one or more synthetic jet ejectors. The system 301 depicted therein comprises a Peltier device 303, a heat sink 305 and first 307 and second 309 synthetic jet ejectors. The heat sink 305 is equipped with a plurality of heat fins 311 which define a plurality of channels 313 such that each channel 313 is formed by a pair of adjacent heat fins 311. The first 307 and second 309 synthetic jet ejectors in the embodiment depicted are disposed at first 315 and second 317 opposing ends of the heat sink 305, respectively.

In operation, the first 307 and second 309 synthetic jet ejectors generate first 319 and second 321 respective sets of synthetic jets which are directed (possibly with the use of nozzles, distributors, manifolds, or other accoutrements) in opposing directions and away from the middle of the heat sink 305. Typically, each synthetic jet in the first 319 and second 321 sets of synthetic jets is directed into one of the plurality of channels 313, so that each channel 313 has synthetic jets of opposing orientation formed therein. Consequently, a flow of air is created which moves into, and in a direction generally perpendicular to, the center of the heat sink 305 as depicted in FIG. 4. In some embodiments, the heat sink 305 may be encased in a housing, and one or more apertures may be provided in the housing near the center of the heat sink 305 to permit or direct a flow of air into the heat sink 305.

FIGS. 5-6 illustrate a second particular, non-limiting embodiment of a thermal management system which utilizes a Peltier device in conjunction with one or more synthetic jet ejectors. The system 401 depicted therein comprises a Peltier device 403, a heat sink 405 and first 407 and second 409 synthetic jet ejectors. The heat sink 405 is equipped with a plurality of heat fins 411 which define a plurality of channels 413 such that each channel 413 is formed by a pair of adjacent heat fins 411. The first 407 and second 409 synthetic jet ejectors in the embodiment depicted are disposed at first 415 and second 417 opposing ends of the heat sink 405, respectively.

In operation, the first 407 and second 409 synthetic jet ejectors generate first 419 and second 421 respective sets of synthetic jets which are directed (possibly with the use of nozzles, distributors, manifolds, or other accoutrements) in opposing directions and towards the middle of the heat sink 405. Typically, each synthetic jet in the first 419 and second 421 sets of synthetic jets is directed into one of the plurality of channels 413, so that each channel 413 has synthetic jets of opposing orientation formed therein. Consequently, a flow of air is created which moves out from, and in a direction generally perpendicular to, the center of the heat sink 405 as depicted in FIG. 6. In some embodiments, the heat sink 405 may be encased in a housing, and one or more apertures may be provided in the housing near the center of the heat sink 405 to permit or direct a flow of air away from the heat sink 405.

FIGS. 7-8 illustrate a third particular, non-limiting embodiment of a thermal management system which utilizes a Peltier device in conjunction with one or more synthetic jet ejectors. The system 501 depicted therein comprises a Peltier device 503, a heat sink 505 and a synthetic jet ejector 507. The heat sink 505 is equipped with a plurality of heat fins 511 which define a plurality of channels 513 such that each channel 513 is formed by a pair of adjacent heat fins 511. The synthetic jet ejector 507 in the embodiment depicted is disposed at a first 515 end of the heat sink 505, respectively.

In operation, the synthetic jet ejector 507 generates a set of synthetic jets which are directed (possibly with the use of nozzles, distributors, manifolds, or other accoutrements) along the longitudinal axes of the channels 513. Typically, each synthetic jet is directed into one of the plurality of channels 513. Consequently, a flow of air is created which moves in a direction generally parallel to the longitudinal axes of the channels 513 as depicted in FIG. 8. As in the previously described embodiments, the synthetic jets create turbulence in the channels 513 which disrupts the boundary layer around the surfaces of the heat fins 511, thus facilitating the dissipation of heat from the heat sink 505 to the ambient environment. In some embodiments, the heat sink 505 may be encased in a housing, and one or more apertures may be provided in the housing on the opposite end from the synthetic jet ejector 507 to permit or direct a flow of air away from the heat sink 505.

FIG. 9 illustrates a fourth particular, non-limiting embodiment of a thermal management system which utilizes a Peltier device in conjunction with one or more synthetic jet ejectors. The system 601 depicted therein comprises a Peltier device 603, a heat sink 605 and a synthetic jet ejector 607. The heat sink 605 may be of various types, including the type described in the previous embodiments.

In this particular embodiment, the Peltier device 603 is placed in contact with a heat source 604 such that the cold side of the Peltier device 603 is in contact with the heat source 604. When power is supplied to the Peltier device 603, a temperature gradient is setup across it. The hot side of the Peltier device 603 is then cooled with the synthetic jet ejector 607, with or without the heat sink 605 being attached to the Peltier device 603.

FIG. 10 illustrates a fifth particular, non-limiting embodiment of a thermal management system which utilizes a Peltier device in conjunction with one or more synthetic jet ejectors. The system 701 depicted therein comprises a Peltier device 703, a heat sink 705 and a synthetic jet ejector 707. The heat sink 705 may be of various types, including the type described in the previous embodiments.

In this particular embodiment, and unlike the previous embodiment, the Peltier device 703 is placed in contact with a heat source 704 such that the warm side of the Peltier device 703 is in contact with the heat source 704. When power is supplied to the Peltier device 703, a temperature gradient is setup across it. The cool side of the Peltier device 703 is then exposed to the synthetic jet ejector 707, with or without the heat sink 705 being attached to the Peltier device 703. The synthetic jet ejector 707 is used to cool one side of the Peltier device 703 to maintain a constant temperature gradient within the limits of the electronics, and the temperature gradient across the Peltier device 703 creates a voltage which is stored and resupplied to the synthetic jet ejector 707.

Various modifications may be made to the above noted devices and methodologies without departing from the teachings herein. For example, various types of synthetic jet ejectors may be utilized, including those with voice coil actuators as well as those with piezoceramic actuators. Moreover, these devices and methodologies may be utilized in various end use applications and in various types of devices. In addition, various heat sinks, nozzles and manifolds having various configurations and geometries may be utilized in these devices and methodologies.

The above description of the present invention is illustrative, and is not intended to be limiting. It will thus be appreciated that various additions, substitutions and modifications may be made to the above described embodiments without departing from the scope of the present invention. Accordingly, the scope of the present invention should be construed in reference to the appended claims. 

What is claimed is:
 1. A thermal management system, comprising: a Peltier device; a heat sink in thermal contact with said Peltier device; and a synthetic jet ejector which directs a synthetic jet onto or adjacent to a surface of said heat sink.
 2. The thermal management system of claim 1, wherein said heat sink comprises a plurality of heat fins, and wherein said synthetic jet ejector directs at least one synthetic jet along the longitudinal axis of a channel formed by adjacent heat fins.
 3. The thermal management system of claim 1, wherein said heat sink comprises a plurality of heat fins, wherein said synthetic jet ejector directs a first synthetic jet in a first direction along the longitudinal axis of a channel formed by adjacent heat fins, and wherein said synthetic jet ejector directs a second synthetic jet in a second direction along the longitudinal axis of said channel.
 4. The thermal management system of claim 1, wherein said heat sink comprises a first plurality of heat fins, and wherein said plurality of heat fins define a plurality of longitudinal channels, each of which is formed by the space between adjacent ones of said plurality of heat fins.
 5. The thermal management system of claim 4, wherein said synthetic jet ejector directs a first plurality of synthetic jets into said longitudinal channels.
 6. The thermal management system of claim 4, further comprising first and second synthetic jet ejectors, wherein said first synthetic jet ejector directs a first plurality of synthetic jets into said longitudinal channels in a first direction, and wherein said second synthetic jet ejector directs a second plurality of synthetic jets into said longitudinal channels in a second direction.
 7. The thermal management system of claim 6, wherein said first and second directions are opposite.
 8. The thermal management system of claim 6, wherein said first synthetic jet ejector directs a first plurality of synthetic jets into said longitudinal channels in a first direction and away from the center of said longitudinal channels, and wherein said second synthetic jet ejector directs a second plurality of synthetic jets into said longitudinal channels in a second direction and away from the center of said longitudinal channels.
 9. The thermal management system of claim 6, wherein said first synthetic jet ejector directs a first plurality of synthetic jets into said longitudinal channels in a first direction and towards the center of said longitudinal channels, and wherein said second synthetic jet ejector directs a second plurality of synthetic jets into said longitudinal channels in a second direction and towards the center of said longitudinal channels.
 10. The thermal management system of claim 6, wherein said first synthetic jet ejector directs a first plurality of synthetic jets into said longitudinal channels in a first direction and towards the center of said longitudinal channels, and wherein said second synthetic jet ejector directs a second plurality of synthetic jets into said longitudinal channels in a second direction and away from the center of said longitudinal channels.
 11. The thermal management system of claim 8, wherein said first synthetic jet ejector is disposed on a first side of said heat sink, and wherein said second synthetic jet ejector is disposed on a second side of said heat sink.
 12. The thermal management system of claim 9, wherein said first synthetic jet ejector is disposed on a first side of said heat sink, and wherein said second synthetic jet ejector is disposed on a second side of said heat sink.
 13. The thermal management system of claim 1, further comprising a heat source disposed on a first major surface of said Peltier device.
 14. The thermal management system of claim 13, wherein said heat sink is disposed on a second major surface of said Peltier device.
 15. The thermal management system of claim 13, wherein said first and second major surfaces are opposing surfaces.
 16. The thermal management system of claim 14, wherein said Peltier device operates such that said second major surface is warmer than said first major surface.
 17. The thermal management system of claim 14, wherein said Peltier device operates such that said first major surface is warmer than said second major surface.
 18. A thermal management system, comprising: a Peltier device having first and second surfaces; a heat source disposed on said first surface; and a synthetic jet ejector which directs a synthetic jet onto or adjacent to said second surface.
 19. The thermal management system of claim 18, wherein said first and second surfaces are first and second major surfaces.
 20. The thermal management system of claim 18, wherein said first and second surfaces are opposing surfaces.
 21. A method for thermally managing a heat source, comprising: providing a thermal management system comprising a Peltier device, a heat sink which is disposed on a first surface of said Peltier device, a heat source which is disposed on a second surface of said Peltier device, and a synthetic jet ejector which directs a synthetic jet onto or adjacent to a surface of said heat sink; and operating the Peltier device such that a temperature gradient is established between said first and second surfaces.
 22. The method of claim 21, wherein the Peltier device is operated such that said first surface is warmer than said second surface.
 23. The method of claim 21, wherein the Peltier device is operated such that said second surface is warmer than said first surface.
 24. The method of claim 21, wherein the Peltier device is operated such that the synthetic jet ejector cools the heat sink sufficiently to maintain an essentially constant temperature gradient within the Peltier device.
 25. The method of claim 21, wherein the Peltier device is operated such that the synthetic jet ejector cools the heat sink sufficiently to maintain a temperature gradient within the Peltier device of less than 15° C.
 26. The method of claim 21, wherein the Peltier device is operated such that the synthetic jet ejector cools the heat sink sufficiently to maintain a temperature gradient within the Peltier device of less than 10° C.
 27. The method of claim 21, wherein the Peltier device is operated such that the synthetic jet ejector cools the heat sink sufficiently to maintain a temperature gradient within the Peltier device of less than 5° C.
 28. The method of claim 21, wherein the Peltier device is operated such that the synthetic jet ejector cools the heat sink sufficiently to maintain a temperature gradient within the Peltier device of less than 2° C.
 29. The method of claim 24, wherein the temperature gradient creates voltage which is supplied to the synthetic jet ejector.
 30. The method of claim 29, wherein the voltage is stored before being supplied to the synthetic jet ejector. 